PROJECT SUMMARY (PILOT PROJECT 1) The overarching goal of this collaborative pilot proposal is the development of a novel approach to treat hepatocellular carcinoma (HCC)?a cancer affecting underrepresented populations in the US at a higher rate. One of the signatures of HCC is the manifestation of global levels of DNA hypomethylation which contributes to tumor progression and metastasis. Although epigenetic therapeutic approaches are on the rise, there are currently no drugs that mechanistically function to reduce DNA hypomethylation. Toward the goal of treating UR populations that are significantly impacted by HCC, we will develop compounds that reduce DNA hypomethylation through a novel therapeutic target. Ubiquitin-like with plant and homeodomain (PHD) and really interesting new gene (RING) finger domains 1 (UHRF1) is a master regulator of the DNA methylome. Overexpression of UHRF1 drives DNA hypomethylation in HCC and tumor progression. UHRF1 is an E3 ligase that affects the negative regulation of the de novo DNA methyltransferase DNMT3A through ubiquitination and degradation. Loss of DNMT3A, in turn, leads to global hypomethylation in cancers. Therefore, as a means toward reducing global hypomethylation in HCC, the focus of this pilot project is the development small- molecules or peptoids that inhibit the UHRF1-DNMT3A protein-protein interaction (PPI). Compounds that inhibit this interaction will rescue DNMT3A levels in HCC cells leading to decreases in genomic hypomethylation and the mitigation of HCC proliferation. To identify compounds that function as UHRF1- DNMT3A inhibitors, we propose in Specific Aim 1 to deploy two discovery platforms in a parallel fashion: DNA- Encoded Chemistry Technology (DEC-Tec) and on-bead peptoid screening. Each of these platforms provides an economical access to a large chemical space that will likely be needed to identify compounds capable of disrupting the UHRF1-DNMT3A interaction. Under the aegis of Specific Aim 2, we will evaluate the biological effects of the UHRF1-DNMT3A inhibitors by executing a suite of biological assays on cancer cell lines generated from HCC tumors obtained from African American and Hispanic/Latino patients. These highly useful cancer cell lines will allow us to develop our compounds within the genetic backgrounds of populations most susceptible to HCC. We will determine the effects of hypomethylation reducing compounds on cellular DNA methylation levels, gene expression, and cancer cell proliferation and apoptosis. Medicinal chemistry will be performed to improve compound potency and biological efficacy leading to approximately six final compounds for which we will conduct preliminary pharmacological studies. The successful completion of this project will afford a novel therapeutic mechanism for the treatment of HCC and have particularly salutary relevance within greatly affected UR populations.